Access door

ABSTRACT

An access door has an outer annular wall frame and an inner annular panel frame. The panel frame has a back flange parallel to but offset rearward from a wall face plane and having a planar front face formed with a forwardly projecting formation. It also has a rim flange projecting generally perpendicular to the plane forward from the outer edge of the back flange and having an annular inner face forming a corner with the front face of the back flange. A rigid panel set in the annular frame has an outer edge juxtaposed with the inner face of the rim flange, a back face spaced from the front face of the back flange, and a front face generally coplanar with a front edge of the rim flange. Adhesive in the space secures the panel to the panel frame.

FIELD OF THE INVENTION

The present invention relates to an access door. More particularly this invention concerns a hatch or panel that is set in a ceiling or wall to allow occasional access to plumbing, wiring, or the like behind the ceiling or wall.

BACKGROUND OF THE INVENTION

In construction it is frequently necessary to provide occasional access to valves, switches, punch-down blocks, and the like that are behind the wall. The access door need not be complex, as it is used infrequently, but must not have a fire rating less than the surrounding wall. It must however be unobtrusive when installed, that is typically be flush so it can be finished like the wall.

Thus a standard such fire resistive access door comprises as described in German patent 37 36 060 or EP 0,567,731 a pair of annular L-section frames, one within the other. The outer wall frame is typically set permanently in the wall, and the inner panel frame is adapted to hold a wall or ceiling panel and is releasably retained in the wall frame by some sort of hinge/latch assembly. In a typical installation the panel frame is adapted to hold one or two thicknesses of standard gypsum board, with in some instances a thin steel plate on the back face of the inset panel.

In order to ensure that the front face of the inset panel is flush with the surrounding wall, it is typically set back a little, to which end the rim flange is made somewhat deeper than the thickness of the inset panel so as to allow for an uneven layer of mastic between it and the front face of the back flange. Thus when the wall is taped, the panel is skim coated with joint compound to bring it out to the right thickness, although it is also known to mud in the inset panel, that is set it in a bed of joint compound. This entails an extra step, and gets the inset panel and steel plate wet, possibly deforming the former and corroding the latter.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide an improved access door.

Another object is the provision of such an improved access door which overcomes the above-given disadvantages, that is which is of simple and economical construction, but wherein the inset panel can be set perfectly flush with the outside plane of the frame.

SUMMARY OF THE INVENTION

An access door according to the invention has an annular wall frame adapted to be set in a wall or ceiling generally parallel to a front plane thereof and an annular panel frame complementary to and fitting in the wall frame and generally of L-section. This panel frame has a back flange generally parallel to but offset rearward from the plane, having an outer edge, and having a substantially planar front face formed with a forwardly projecting formation and a rim flange projecting generally perpendicular to the plane forward from the back-flange outer edge and having an annular inner face forming a corner with the front face of the back flange. A rigid panel set in the annular frame has an outer edge juxtaposed with the inner face of the rim flange and a back face bearing on the formation and spacedly juxtaposed with the front face of the back flange. This back face forms an annular space extending along the projecting formation. The panel also has a front face generally coplanar with a front edge of the rim flange. An annular mass of adhesive in the annular space between the front face of the back flange and the back face of the panel secures the panel to the panel frame.

Thus with the system of this invention the front face of the panel will lie in the same plane as the front edges of the frames, eliminating the need for any filling of the panel frame. The use of an adhesive rather than the typically used joint compound allows this exact positioning and ensures that the panel will be very solidly connected to the panel frame.

According to the invention the rim flange is formed offset forward of the corner with an inwardly projecting ridge. The mass is wholly trapped rearward of the ridge. More particularly, the mass is wholly trapped between the formation and the ridge. Thus any leaking out is largely avoided, making the assembly and installation very neat, even when the back face of the panel is covered with a steel plate.

In accordance with the invention the formation and ridge extend annularly around the respective flanges of the panel frame. The formation itself is an annular ridge. The adhesive itself is preferably a mixture of aluminum silicates and water glass (sodium silicate) that cure and harden at standard ambient temperature and atmospheric conditions. The adhesive should be fire-resistant, like the panel.

The formation according to the invention can be a multiplicity of teeth projecting forward from the back flange and poking into the back face of the panel. These teeth are punched out of the back flange. In addition the back flange and/or the rim flange can be formed with throughgoing holes through which the adhesive can be injected between the panel and the panel frame. This makes it easy to inject the necessary adhesive into the space behind the panel without making a mess of the access door. In fact, when the formations are teeth poking into the panel, the hold is so good that spot gluing around the panel is sufficient to hold it solidly in place.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a front view of an access door according to the invention;

FIG. 2 is a section taken along line II-II of FIG. 1;

FIG. 3 is a view like FIG. 2 showing a variant on the structure in accordance with the invention; and

FIG. 4 is a large-scale front view of a front face of the back flange of the structure of FIG. 3.

SPECIFIC DESCRIPTION

As seen in FIGS. 1 and 2, an access door according to the invention has a basically L-section, rectangular, and annular steel wall frame 1 adapted to be set in a wall or ceiling 2 defining a front wall or ceiling plane P. A steel inner frame 4 also of L-section fits complementarily inside this frame 1 and holds a rectangular panel 3, here a piece of standard fire-rated gypsum board, having a front face 3 a lying on the plane P, a parallel back face 3 b, and an outer edge 3 c. Unillustrated hinges and/or latches secure the inner frame 4 in the outer frame 1.

In accordance with the invention the inner frame 4 has a back flange 5 lying in a plane parallel to but offset rearward from the plane P and an annular rim flange 6 perpendicular to the plane P and extending forward from an outer edge of the back flange 5 to a front edge lying on the plane P. The back flange 5 is provided with a forwardly projecting formation, here annular ridges 7 that project toward and normally directly engage the back face 3 b of the panel 3. In addition an inner face of the rim flange 6 is formed with inwardly directed ridges 10 forming a space 11 extending around a corner 8 between the flanges 5 and 6. The ridges 10 are lower than the ridges 7 and the space defined between the ridges 10 and formation 7 extends annularly around the panel frame 4 and is of L-section. This corner 8 is filled with an annular thin mass 9 of adhesive that adheres to the back face 3 b and to the outer edge 3 c, although of course the strongest bond is to the face 3 b. This mass 9 is effectively captured in the corner 8 between the ridges 7 and 11, ensuring perfect positioning of the panel 3 with its face 3 a on the plane P with the front edges of the frames 1 and 4.

FIGS. 3 and 4 show a variant where the ridges 7 are replaced by punched out pointed teeth or tabs 12 that actually poke into the back face 3 b of the panel 3. In addition the flange 4 is formed with throughgoing holes 13 through which the adhesive mass 9 can be injected for mounting of the panel 3. 

1. An access door comprising: an annular wall frame adapted to be set in a wall or ceiling generally parallel to a front plane thereof; an annular panel frame complementary to and fitting in the wall frame, generally of L-section, and having a back flange generally parallel to but offset rearward from the plane, having an outer edge, and having a substantially planar front face formed with a forwardly projecting formation, and a rim flange projecting generally perpendicular to the plane forward from the outer edge and having an annular inner face forming a corner with the front face of the back flange; a rigid panel set in the annular frame and having an outer edge juxtaposed with the inner face of the rim flange, a back face bearing on the formation, spacedly juxtaposed with the front face of the back flange, and forming an annular space extending along the projecting formation, and a front face generally coplanar with a front edge of the rim flange; and an annular mass of adhesive in the annular space between the front face of the back flange and the back face of the panel.
 2. The access door defined in claim 1 wherein the rim flange is formed offset forward of the corner with an inwardly projecting ridge, the mass being trapped rearward of the ridge.
 3. The access door defined in claim 2 wherein the mass is wholly trapped between the formation and the ridge.
 4. The access door defined in claim 3 wherein the formation and ridge extend annularly around the respective flanges of the panel frame.
 5. The access door defined in claim 1 wherein the formation is an annular ridge.
 6. The access door defined in claim 1 wherein the formation is a multiplicity of teeth projecting forward from the back flange and poking into the back face of the panel.
 7. The access door defined in claim 6 wherein the teeth are punched out of the back flange.
 8. The access door defined in claim 6 wherein the back flange is formed with throughgoing holes through which the adhesive can be injected between the panel and the panel frame.
 9. The access door defined in claim 8 wherein the rim flange is formed with throughgoing holes through which the adhesive can be injected between the panel and the panel frame.
 10. The access door defined in claim 1 wherein the adhesive is a mixture including aluminum silicates and sodium silicate. 